From 3b621ccabdccb34891bb58865a9654a09c2b7279 Mon Sep 17 00:00:00 2001 From: Bin Meng Date: Thu, 22 Jan 2015 11:29:41 +0800 Subject: x86: Test mtrr support flag before accessing mtrr msr On some x86 processors (like Intel Quark) the MTRR registers are not supported. This is reflected by the CPUID (EAX 01H) result EDX[12]. Accessing the MTRR registers on such processors will cause #GP so we must test the support flag before accessing MTRR MSRs. Signed-off-by: Bin Meng Acked-by: Simon Glass --- arch/x86/include/asm/mtrr.h | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) (limited to 'arch/x86/include') diff --git a/arch/x86/include/asm/mtrr.h b/arch/x86/include/asm/mtrr.h index 3c11740..fda4eae 100644 --- a/arch/x86/include/asm/mtrr.h +++ b/arch/x86/include/asm/mtrr.h @@ -65,7 +65,6 @@ void mtrr_open(struct mtrr_state *state); * * @state: Structure from mtrr_open() */ -/* */ void mtrr_close(struct mtrr_state *state); /** @@ -76,6 +75,8 @@ void mtrr_close(struct mtrr_state *state); * @type: Requested type (MTRR_TYPE_) * @start: Start address * @size: Size + * + * @return: 0 on success, non-zero on failure */ int mtrr_add_request(int type, uint64_t start, uint64_t size); @@ -86,6 +87,8 @@ int mtrr_add_request(int type, uint64_t start, uint64_t size); * It must be called with caches disabled. * * @do_caches: true if caches are currently on + * + * @return: 0 on success, non-zero on failure */ int mtrr_commit(bool do_caches); -- cgit v1.1